Erin Vogel, Ph.D. Research Scientist, Dow Coating Materials
Solvent borne (SB) alkyd resins are widely used in industrial coatings because of their excellent gloss, adhesion, and wetting properties as well as compatibility with other resin types. In many regions, however, the consumption of SB alkyds has diminished as stringent environmental regulations have driven adoption of low VOC systems. In some instances, waterborne (WB) alkyd emulsions have replaced SB alkyd systems; however, they typically do not offer the same performance. Dow has developed technology to disperse short, medium, and long oil alkyd resins with minimal surfactant and no polymer modification. Pigmented WB alkyd coatings formulated with these resins demonstrate comparable properties to those of conventional SB alkyd coatings. For example, short and medium oil alkyd dispersions formulated into ultra-low VOC (<10 g/L) coatings give thin films (1 mil) that display excellent gloss, adhesion, flexibility, and solvent resistance as well as superb salt spray resistance (>300 hr.).